Photoperiodic Cycles

Photoperiodic Induction If a plant is exposed to periods of light and darkness long enough to promote flowering, it is said to be photoperiodically induced, and the minimum duration of light needed to initiate floral primordia is called inductive cycle photoperiod. It was observed that if a short-day plant growing under long-short conditions is temporarily transferred to short day conditions ...

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Funaria

Funaria Occurrence Funaria is  terrestrial moss. It grows in the form of bright green velvety patches in shady and damp places. Genus Funaria is composed of 117 species. Funaria hygrometrica is most common and worldwide species. It grows well on burnt soil. It grows best in the presence of calcium, potassium, nitrogen and phosphorus. Vegetative structure of gametophyte Structure of ...

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fossils

Fossil & Fossilization – importance , types and divisions PALEOBOTANY The study of fossils of plant life of the geologic past is called paleobotany. Paleobotany tells us the story of preserved vestiges of the plant life of the past. In simplified language paleobotany may be defined as a branch of botany which deals with the study of such plants which ...

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pteridophytes

Occurrence and evolution of Pteridophytes Pteridophyta is a group of ancient plants. They formed the dominant part of the earths during Palaeozoic and Mesozoic periods. Majority of Pteridophytes became extinct. They are preserved in the form of fossils or coal deposits. Only a few living Pteridophyta are left. General structure The vegetative plant body is a sporophyte in Pteridophytes. Sporophyte ...

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Discovery of Photoperiodism in Plants

Photoperiodism is the response of a plant to the relative length of light and dark periods to produce flower. The relative length of day and night to which a plant is exposed is called the photoeriod. Photoperiodism is a photobiological process – a process that involves absorption of light by a receptor (usually a pigment) that results in activation of ...

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Chemical Nature of Plasma Membrane

Physio Chemical Nature of Plasma Membrane The plasma membrane surrounds the cell. Chemically plasma membrane is composed of: Protein: 60 to 80% Phospholipids: 20 to 40% Cholesterol is in small amount Carbohydrates is in small amount Different models were put forward about the physiochemical nature of plasma membrane. Old Concepts Charles Overton: He found that the substances which dissolved in ...

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Psilopsida Botany-Leptosporangiate fern

PSILOPSIDA TYPE PSILOTUM Occurrence Psilotum is distributed in tropical and subtropical regions. It may grow as an epiphyte on the bark of trees. It also grows on soil where humus is abundantly available. General structure The plant body is sporophyte. The plant is a small shrub. The plant body is differentiated into rhizome and aerial branches. 1.  Rhizome: Rhizome is ...

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Leaf Structure

STRUCTURE OF LEAF Different groups of plants hake different variations in the internal structure or foliage leaves. Hie leaves show different evolutionary adaptations for different environmental conditions. The leaf tissues are divided into three fundamental systems. These are epidermal. mesophyll and vascular tissues. Epidermis The leaf tissue is covered on both sides by epidermis. The epidermis is fully activated in ...

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Cytoplasm

Physio-Chemical Nature of Cytoplasm The living content of the protoplasm between the plasma membrane and nucleus is called cytoplasm. Living content of eukaryotes is divided into nucleus and cytoplasm. These living contents (nucleus and cytoplasm) collectively forms protoplasm. The cytoplasm has four components: Cytomembrane System It consists of well-defined structures, such as endoplasmic reticulum, mitochondria, plastids, Golgi apparatus, vacuoles and ...

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Peroxisome And Glyoxisomes

Peroxisome Peroxisomes are cytoplasmic organelles. De-Duve and co-workers isolated peroxisome from liver cells and some other tissues. They are present in both animals and plants. They are also found in protozoa, yeast and many types of cells of higher plant. Structure: Peroxisomes are enclosed in a single membrane. Their size is 0.5 μm in diameter. In some mammalian tissues peroxisomes ...

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